Merge pull request #126 from matrix-org/csauth

CAPTCHA_SETUP

register_new_matrix_user

static/client/register/style.css

synapse/api/auth.py

synapse/api/constants.py

synapse/api/errors.py

synapse/config/captcha.py

synapse/config/email.py

synapse/config/homeserver.py

synapse/handlers/__init__.py

synapse/handlers/auth.py

synapse/handlers/identity.py

synapse/handlers/login.py

synapse/handlers/register.py

synapse/http/client.py

synapse/http/server.py

synapse/push/__init__.py

synapse/push/pusherpool.py

synapse/rest/client/v1/base.py

synapse/rest/client/v1/pusher.py